This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-271817, filed Sep. 7, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a positionable-axle bicycle ergometer suitable for training, for example, sprinters.
The results of analysis concerning the motion of elite sprinters of the world, or the result of research of sports science concerning the relationship between leg muscular strength and running ability clarify that it is necessary, to achieve a good score in a sprint, to strengthen the extension muscles (hamstrings) and the flexor muscles (quadriceps) of the thighs connected to the hip joint, so as to enable the thighs to move at high speed.
FIG. 6 is a schematic side view illustrating the motion trajectory of the hip, knee and ankle of a top sprinter, using the position of the greater trochanter of the hip joint as a fixed reference point. As shown in FIG. 6, zones AB, BC, CD, DE and EA correspond to xe2x80x9cswing-down stagexe2x80x9d, xe2x80x9cground-contact stagexe2x80x9d, xe2x80x9cearly kick-up stagexe2x80x9d, xe2x80x9clate kick-up stagexe2x80x9d, and xe2x80x9cswing-back stagexe2x80x9d, respectively. The xe2x80x9cground-contact stagexe2x80x9d is divided into xe2x80x9cearly ground-contact stage (landing stage)xe2x80x9d in which a landing motion is executed, and xe2x80x9cmiddle/late ground-contact stage (kick stage)xe2x80x9d in which a kick motion is executed. During the running motion, xe2x80x9cswing-down stagexe2x80x9d AB, xe2x80x9cground-contact stagexe2x80x9d BC and xe2x80x9cearly kick-up stagexe2x80x9d CD require much muscular force, whereas xe2x80x9clate kick-up stagexe2x80x9d DE and xe2x80x9cswing-back stagexe2x80x9d EA require little muscular force.
Irrespective of the fact that the importance of the actions of the hip joint extension muscles, mainly hamstrings, is indicated, no conclusive method for strengthening them has yet been found. Not so appropriate training methods, using a rubber tube or a conventional training machine (such as a leg curl machine), are still being employed.
As indoors leg training machines for athletes, especially sprinters, treadmills (endless running plates), bicycle ergometer, step-type exercise ergometer and cross-country-ski type training machines, etc. are cited.
The treadmill is a load application machine equipped with a motion belt having its rotational speed and inclination made adjustable, on which the exerciser walks or runs. Many people run or walk on the treadmill to increase their body stamina.
The bicycle ergometer is a load application machine utilizing pedaling of a fixed-axle bicycle. This machine is used to strengthen leg muscles or to increase body stamina.
In the step-type exercise ergometer (for example, a striding-type exercise apparatus disclosed in U.S. Pat. No. 5,419,747), the exerciser, while standing, alternately steps on the left and right steps of the ergometer, as if they were walking up stairs. The feet of the exerciser repeat a vertical motion within a predetermined range along an arc.
In the cross-country-ski type training machine, the exerciser slides their legs forward and backward in a large angle in a reciprocated manner, and moves their arms as if holding ski poles. Since the legs are horizontally moved on the floor forward and backward, a muscle training effect can be obtained in a position in which the exerciser is kept in contact with the floor.
The above-described training methods using conventional training machines are disadvantageous in the following points.
In the case of the treadmill, the exerciser cannot automatically correct their style of running, and further a positive muscle training effect cannot be expected.
In the bicycle ergometer, since the radius of rotation in the pedaling exercise is constant, the range of motion of muscles is limited, compared with the running motion. Specifically, in the pedaling exercise, a main pedal driving force is used in a motion range corresponding to the swing-down stage and the landing stage (early ground-contact stage), whereas only a small muscle force is used in the kick stage (late ground-contact stage). This differs from the ideal running motion.
In the step-type exercise ergometer, the feet of the exerciser repeat a vertical motion of a predetermined range along an arc. In other words, the exerciser executes a stepping motion in one place along part of a circle about an axis of rotation. This differs from the trajectory of the legs in the motion of running or walking. Accordingly, it is difficult to totally and specifically train the muscles and nerves used for running or walking.
Using the cross-country-ski type training machine, the exerciser cannot imitate a running motion, notably, the swinging up of the leg after the ground-kicking motion, followed by the forward swinging down.
It is the object of the invention to provide a bicycle ergometer capable of strengthening leg muscles and muscles relating to the motion of the pelvis or the hip joint, thereby enhancing the ability of walking or running.
The bicycle ergometer of the present invention enables the exerciser to walk or run with an ideal leg load and trajectory, thereby enhancing their ability of walking or running.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.